Titanium pigments



?atented;Nov. 29, 1938 warren stares err-rice TITANIUM PIGmN'ES Georg Moder,

assignor to Leverkusen-K. G. Work, Germany, Ii. G. Farbenlndnstrie Aktiengesell= schaft, Frankfort-on-the-Maln, Germany No Drawing. Application April 1 5,

No. 137,044. In Germany April 1'7,

,5 Claims.

' lizing rhombohedrallyand having the crystalline structure of corundum, are-prepared. In said mixed crystals the titanium sesquioxide can be partially replaced by one or more of the following metal oxides which have a similar crystal lattice structure: A1203, CI203, FezOa, V203 and All these mixed crystals constitute very good pigments. Mixed crystals consisting of Ti02 and some tenths per cent of Ti2O3, form pigments of intense coloration. When increasing the T1203 content the shade becomes more intense. Depending upon the composition of the mixed crystals, there result pigments of black to blue shades, which show a good covering power and surprisingly good properties with regard to fastmess to chalking and to the influence or cement.

The mixed crystals in which one part of the T1203 is replaced by the A1203, CrzOa, FezOs, V203 and BhzOa-compohents yield pigments from blackishgrey, pigeon blue, yellow, gold-yellow, orange to white shades. All these vari-colored and white pigments show surprisingly good color retention properties. It follows that the mutual neutralization of the lattice energies of the crystal1o graphic structure of the elements produces .very stable pigments which meet individual specific requirements and are therefore technically valu able. They can be used as glazing, enamel, and

anti-rust pigments as well as pigments for coloring artificial silk. When imbedded in artificial sill: the sill: is delustered and has a beautiful shade. ffiiorably influence the properties of the artificial s The new pigments are obtained by causing the single components to react one upon the other at an elevated temperature, whereby care must be taken that no oxidation takes place. 'One may produce such a pigment, for example, by making titanium hydroxide into a paste with a solution of a titanous salt and then heating the mixture to about 800 to 1100" C. while excluding oxidizing influences, for instance by treating the mixture in a reducing or inert atmosphere and eventually in the presence of feducing substances, such as carbohydrates, SbzOa, AS203 and so on. The reaction can also be performed by intimately mixing TiO2 with corresponding quantities of Al, Cr, Fe, V and/or Rh in a finely divided metallic state,

Furthermore the pigments do not un-' 1937, Serial such as powder, dust, colloidal solutions or the like and heating this mixture with the exclusion of oxygen for a short time, for instance about one hour to 800 to 1100 C. or causing the mixture to burn oil in itself after previous priming.

The following examples illustrate the invention, without restricting it thereto.

Example 1 trample 2 20 kgs. of titanium hydroxide containing about 14% of water are made into apaste with 2o liters of a titanous chloride solution containing about '10 g. of Th0: per liter to which solution about 250 g. of CrzOs are added in the form or a soluble salt. Then themixture iscalcined with the exclusion of oxidizing influences for about one hour at 900 to 966. A reddish-yellow pigment is thus obtained which is so stable that it can be used as pigment ior enamels and glazings to which it confers a gold-yellow coloration.

. L'sampl 3 20 kgs. of titanium hydroxide containing about 14% of water are well mixed with 2 kgs. of A1(OH)3 and then made into a paste with 20 to liters of a titanium chloride solution in the same concentration as indicated in Example 2. When calcining the mixture for" l to 2 hours to 900 to 950, a white pigment of good covering power is" obtained which is well suitable as a paint for buildings and the like.

Example 4 I 33% kgs. of T102 are made into a paste with 7 about 40 to '70 liters of a titanous chloride solu-' texture. It is suitable as anti-rustpaint.

imbedded in artificial silk the silk has a dull lustre and beautiful black coloration.

I claim:

1. Mixed crystals of titanium dioxide, crystallizing tetragonally, and titanium sesquioxide, crystallizing rhombohedrally and having the crystalline structure of corundum, in which apart of the titanium sesquioxide is replaced by a metal oxide having a similar crystal lattice structure selected from the group consisting of: A1203, CI'2O3, F8203, V203 and RhzOs.

2. Mixed crystals of titanium dioxide, crystallizing tetragonally, and a minor amount of titanium sesquioxide, crystallizing rhombohedrally and having the crystalline structure of corundum, in which a part of the titanium sesquioxide is replaced by a metal oxide having a similar crystal lattice structure selected fromthe group consisting of A1203, CrzOs, FezOa, V203 and RhzOs.

3. Process of preparing mixed crystals of titanium dioxide, crystallizing tetragonally, and titanium sesquioxide, crystallizing rhombohedrally and having the crystalline structure of corundum,

which comprises heating titanium dioxide with a reducing agent of the group consisting of a titanous compound, Al, Cr, Fe, V and Rh to a temperature of about 800 to about 1100 C., while excluding oxidizing influences.

4. Process of preparing mixed crystals of titanium dioxide, crystallizing tetragonally, and titani-.

um sesquioxide, crystallizing rhombohedrally and having the crystalline structure of corundum, which comprises heating titanium dioxide with a titanous compound to a temperature of about 800 GEORG MEDER. 

